How to Determine Septic Absorption Field Size

A conventional septic tank performs roughly 45% of the sewage treatment or less at a private home served by a septic system. The rest of the wastewater treatment and ultimately the liquid disposal occurs in the drainfield.

Septic Leach Field or Septic Absorption Field Size: How large does the drainfield need to be?

The size of the absorption field needed (in square feet of area, presumably
also unencumbered by trees, driveways, buildings, etc.) can range considerably depending on the soil percolation rate. Sketch at left - USDA.

A lot with a good percolation rate or "perc" of perhaps one inch of percolation
in three minutes might require about 450 square feet for a typical three bedroom home. If the same home were
built where there was a poor a soil percolation rate of an hour per inch, 900 square feet or more might be required
for the absorption area.

The leach field is a series of trenches that may be up to 100-feet long and 1 foot to 3 feet in width, separated by six feet or more, depending on local requirements, and sometimes constructed leaving space between the original lines to install replacement leach lines when needed. - paraphrasing USDA.

Drainfield size and location also have to take into account local zoning - setback requirements from property borders, setbacks from
streams, wetlands, wells, water supply lines, and other encumbrances.

Septic Drainfield Design Basics: septic trench line specifications

Below we summarize the basics of septic drainfield design, followed by more detailed septic field design specifications for common types of drainfields or soakaway beds.

In the most common design of drainfield, perforated pipes are buried in gravel-filled trenches to form the drainfield.

[Click to enlarge any image]

Perforated septic drainfield pipes are
placed in gravel-filled trenches across the slope line of sloped property (so that all of the effluent doesn't simply rush down to and leak out at the end of the drain
line pipe).

Drainfield trench piping slope specifications: While some experts describe the bottom of these trenches as "level" in practice they are dug to slope slightly, perhaps
1/8" per foot or less.

The sketch at left shows a cross section of a septic drainfield or soakaway field or leach field trench - the common name varies by geographic location and custom.

Septic drainfield pipe hole or perforation position: up or down? As you see in the sketches shown here, the septic leaching bed perforated pipe is placed on a bed of gravel and then covered with more gravel. Do not place the pipe at the bottom of the trench before any gravel is placed therein.

We like to place the pipe with perforations at the 5 o'clock and 7 o'clock positions so that we're not simply storing and collecting sludge and effluent in the pipe bottom; by not placing the perforated septic drainfield pipe with one of its rows of holes facing directly down (at 6 o'clock position) we defer the clogging of the pipe effluent drain openings.

Our second drainfield sketch (left, USDA) shows a slightly different view, in this case an isometric cross-section drawing of a septic drainfield trench.

Septic drainfield trench depth specification: A typical septic drainfield trench is 18 to 30 inches in depth, with a maximum soil cover over the disposal field of 36"; or per the USDA, 2 feet to 5 feet in depth. At REFERENCES we cite these sources.

In some climates such as northern Minnesota we have observed drainfield trenches placed much deeper - unfortunately meaning that while effluent disposal may be protected from freezing, effluent treatment may be marginal.

Regardless of actual drainfield trench width, for design purposes each linear foot of drainfield line is considered to to provide one square foot of drainage area (by many building code or health department septic design approving authorities).

Septic drainfield trench spacing: The trenches are dug about 6 feet apart on center (center of pipe to center of next pipe) which allows,
in good design, space for a set of replacement trenches to be placed between the original ones when the first set fails.

Septic drainfield trench length: The maximum length of a trench is typically about 150 feet but we have found installations that were three times that length.

Some writers opine that the maximum septic trench line is 100 feet. A realistic answer is, it depends - on site and soil conditions.

Septic drainfield gravel specification: typically, washed gravel, 3/4" to 2 1/2" (pretty big) gravel is placed for a depth of 12" under the drain line piping ("septic drain tile" in some references).

The pipe is then covered by additional gravel to a depth of at least 2" over the top of the septic drain line before backfill is added. Some septic installers place a geotextile over or around the gravel and pipe to reduce clogging by dirt infiltration from the septic trench backfill.

Septic drainfield pipe or drain tile connections: modern drainfields constructed using perforated plastic pipe are comprised of pipe sections that are physically connected together: one end of each pipe is expanded to slip over the diameter of its mating section.

Older traditional drainfields made of other perforated piping were constructed by laying perforated pipe end to end, with abutting pipe ends spaced 1/4" apart and protected from backfill soil by a layer of roofing felt.

The sketch above shows a cross section of a typical drainfield trench, and places below the trench the critical
biomat as well as other septic field design areas and considerations. (Source US EPA who in turn obtained the drawing from Ayres Associates)

Where lot space does not permit drainfield trenches such as I've just described, a septic engineer may specify that seepage pits
or galleys are to be installed. These fit in a smaller space since a single pit may be 6' to 8' in diameter.

But the depth to which effluent is
being delivered (4' or more) means that the sewage effluent is unlikely to be fully treated by a biomass. These systems may successfully "dispose" of
effluent but they are probably not adequately "treating" it.

The Biomat: The formation, clogging, and measures to protect and extend the life
of the biomat, or organism layer below and around soil absorption system effluent discharge piping
is discussed at Septic System Absorption System Biomat Formation
as a subchapter of this text.

Summary Table of Typical Disposal Field Specifications

Drainfield / Soakbed / Seepage Bed Component

Specification

Comments

Absorption trench (leach line)

Maximum Length

100 Feet

Maximum earth cover fill thickness (depth) over Trench Top

36 inches

Maximum slope of trench (grade)

4 inches / 100 feet

Minimum slope of trench (grade)

level

Minimum bottom width of trench

18 inches

Minimum spacing between lines, edge to edge

8 feet

Minimum usable absorptive material below trench bottom

12 inches

Minimum filter material over drain pipes or lines

12 inches

Maximum distance from drain line to trench edges

18 inches

Other Soakbed / Leachfield Construction Specifications

Base material under & around drainfield piping: stone or equivalent aggregate:
Before drain lines are laid, crushed stone, gravel, slag,
or similar filter materials clean in appearance and varying in size
from three-quarter inch to two and one-half inches and otherwise
acceptable to the Shasta County Director of Environmental Health
shall be placed in the trench to the depth and grade required by
this paragraph:

The filter material in the leaching field shall
conform to the following standards:

The filter
material shall have a cleanness value of at least 70 using test
18
method No. Calif. 227-E method of test for evaluating cleanness of
course aggregate.
The gravel shall be placed in the trenches in a
manner which will leave the sides and bottom free from deposits of
rock dust or cement dust.

"Effective size" for the purpose of
these Standards is that size of grain which is larger than 10
percent of the material by weight.

The uniformity coefficient for
the purpose of these Standards is that sieve that passes 60 percent
of the material divided by sieve size that passes 10 percent of the
material.
Drain lines shall be completely encased by filter
material to prevent closure of voids with earth backfill. - Shasta County cited below

Filter material over drainfield lines before backfillStraw, newspaper, untreated building paper or similar
materials shall be placed over filter materials in leach lines or
seepage pits prior to backfilling. - op. cit

Covering over drainfields:The site of the initial and replacement disposal fields
shall not be covered by asphalt or concrete or subject to vehicular
traffic or other activity which would adversely affect the soil. - Op. Cit.
See

Includes additional detailed specifications for the leach field or disposal area including setbacks, proximity to bodies of water, exposure to flooding, percolation rates, seasonal high water table, soil perc test specifications, groundwater monitoring, requirement for height above seasonal high groundwater, soil analysis, prohibition of seepage pits, and other septic system design specifications for septic tank & disposal field specifications. (Excellent detailed specifications.

Septic Drainfield Inspection Ports

A high quality septic drainfield or leach bed design includes inspection ports or pipes that permit inspection of the condition of the field. Vertical pipes are placed, usually at the end of each drainfield trench or section or at critical or suspect areas near the drainfield to permit monitoring of liquid levels in the drainfield trenches.

If a few ports are included outside the drainfield area they will aid distinguishing between a drainfield suffering local effluent saturation from an area groundwater problem that also impedes the drainfield operation.

Some installers trim the inspection ports to ground level, sealing each with a removable cap to permit inspection of the drainfield condition without interfering with mowing.

Detailed Specifications for Septic Absorption Field Designs

The following specification for septic drainfields or leaching beds, of various types, designs, and depths,
is adapted and expanded from: New York State Appendix 75-A.8 Subsurface treatment, of New York's Wastewater Treatment Standards for Individual
Household Systems.

We also include excerpts and references from other U.S., Canadian, and other authorities at state and provincial levels, and from the US EPA Onsite Wastewater Treatment Systems Manual which is available free from the US EPA and is provided in a linked-to copy at the REFERENCES section of this article.

(a) General Information

All effluent from septic tanks or aerobic
tanks shall be discharged to a subsurface treatment system. Surface
discharge of septic tank or aerobic unit effluent shall not be approved
by the Department of Health or a local health department acting as its
agent.

(1) Site requirements for Septic Drainfields

(i) The minimum distances that absorption fields shall be separated from
other facilities are shown in Figure 1 and Table 2.

(ii) A minimum of four feet of useable soil shall exist above bedrock
and groundwater with a minimum separation of two feet to the lowest part
of any trench.

(iii) Absorption fields shall not be built under driveways, parts of
buildings or under above-ground swimming pools or other areas subject to
heavy loading. Surface waters shall be diverted from the vicinity of
the system.

(2) Design criteria for Septic Drainfields

(i) The required length of absorption trench is determined from Table 4A
based upon the percolation test results and confirmed by the soil
evaluation. The maximum trench width for design purposes shall be 24
inches. Only 24 inches shall be allowed for absorption area
calculations. Where trenches exceed 24 inches in width, calculations of
absorptive area shall be based on a width of 24 inches.

(ii) Adjacent trenches shall be separated by at least four feet of
undisturbed soil. Individual trenches shall be constructed parallel to
the ground contours with trench bottoms as near level as possible. They
need not be perfectly straight but abrupt changes in direction shall be
avoided.

Septic Drainfield Trench Length Specifications

This table specifies the necessary length of a conventional
septic drainfield trench as a function of the soil percolation rate
and the anticipated daily wastewater flow from the building served.

An Alternate Table for Determining Septic Drainfield Size

Determining the required size of a leach field is a bit more complicated. The first thing to consider is the nature of the soil in which the leach
field is to be constructed. Because water has to be absorbed in the soil, we need to know how fast it can be absorbed. This is called the percolation
rate and is expressed as the time it takes for water in a test hole to decrease in level by one inch (minutes/inch).

We must also know the type of
soil and whether seasonal changes in the natural level of groundwater will interfere with the satisfactory operation of the system. Seasonal
groundwater must be more than four feet from the bottom of the leach field trenches.

Judgments regarding the soil conditions and percolation rates are
best left to a professional. If the soil percolates very quickly, (less than one minute per inch) or very slowly (greater than 60 minutes per inch) it
will not be possible to install a standard leach field in the existing soil.

We must now determine the amount of water that has to be absorbed each day. As with the septic tank sizing, there are also "rules of thumb" that can be
used to find out how much water must be absorbed each day for each bedroom in the house (expressed as gallons per day per bedroom).

For older houses
(built before 1979) we must allow 150 gallons per day (gpd) per bedroom.

For houses where the toilets are limited to no more than 3.5 gallons per
flush and the faucets and showerheads are limited to 3 gallons per minute or less, we must allow 130 gpd per bedroom.

For houses with water-saving
toilets that use only one gallon per flush we allow 90 gpd per bedroom.

The required flow rate is found by multiplying the appropriate flow by the
number of bedrooms (in this case, we do not have to count a garbage disposal as a bedroom).

Knowing the rate at which water can be absorbed by the soil (the percolation rate) and the flow rate (in gallons per day), we can use the
following table to calculate how many square feet of absorption field is needed. [Readers will notice that this table is similar to but less detailed than our typical state or board of health table above at TABLE 4A.]

What is the Required Size of the Septic Leach Field?

Absorption
Percolation
Minutes per Inch

Allowable
Application Rate - Gallons
per Day per Square Foot

> 1

Not Acceptable

1 - 5

1.2

6 - 07

1.0

8 - 10

0.9

11 - 15

0.8

16 - 20

0.7

21 - 30

0.6

31 - 45

0.5

46 - 60

0.45

Notes:

Soil with a percolation rate less than 1 minute per inch or more than 60 minutes per inch is unsuitable for a conventional system.

This table specifies the allowable wastewater application rate into the
soil of a conventional septic system drainfield as a function of the soil
percolation rate for percolation rates between 1 minute per inch to 60 minutes per inch.

Soils
with a percolation rate of less than 1 minute per inch should not be used for a
conventional septic drainfield.

Readers will note that this table considers only
the dimensions of the bottom of the drainfield trench in considering the effective
soil absorption area.

Typically a conventional drainfield trench is 2 ft. wide, so
the effective absorption area is simply 2 ft. x field-length in ft. Beware that in some jurisdictions, when calculating required drainfield trench lengths the authorities may consider the trench width to be a nominal one-foot wide regardless of its actual width.

Soil with a percolation rate of less than 1 minute / inch is un-suitable for a conventional septic system design: the wastewater will be absorbed into surrounding soil too rapidly to permit adequate treatment.

(3) Materials used for Septic Drainfields

(i) Perforated distributor pipe shall be used in the trenches. Solid (non-perforated) pipe shall be used between the distribution box and the
trenches.

Perforated pipe shall be made of rigid or corrugated plastic and be labeled as fully meeting ASTM standards for use in septic
systems. Corrugated plastic pipe delivered in coils is not to be used unless provision is made to prevent the recoiling or movement of the
pipe after installation.

(iii) The aggregate shall be covered with a material that prevents soil from entering the aggregate after backfilling, yet must permit air and
moisture to pass through.

The preferred material for covering the aggregate is a permeable geotextile. Untreated building paper or a four
inch layer of hay or straw is acceptable. Polyethylene and treated building paper are relatively impervious and shall not be used.

(4) Construction of Septic Drainfields

(i) Trench locations and depths should be marked by stakes before the trenches are excavated. The natural surface shall not be significantly
disturbed. If the site is re graded or similarly disturbed, the soil shall be allowed to stabilize and new percolation tests conducted.

(ii) The trench depth shall be as shallow as possible, but not less than 18 inches. At least six inches of aggregate is placed below the
distribution line and two inches above the line. The earth cover over the aggregate should not exceed 12 inches in order to enhance natural
aeration and nitrogen uptake by plant life.

Trenches shall be excavated to design depth with bottoms practically level. Heavy equipment shall be kept away from the field because the weight may permanently alter
soil characteristics due to compaction, cause trench cave-ins, and/or mis-align and break pipe.

(iii) Trench bottoms are to be raked and immediately covered with at least six inches of aggregate.

(iv) Any smeared surfaces on the trench walls are to be raked. Distributor lines are carefully placed on the aggregate and covered with
aggregate to a depth of at least two inches over the top of the pipe. Additional aggregate may be required to bring the top of the aggregate
to within six to 12 inches of the surface.

(v) In gravity distribution systems, the pipe shall be carefully sloped at between 1/16 inch and 1/32 inch per foot. Grades shall be determined
by an engineer's level, transit or carpenter's level.

(vi) After the upper aggregate is placed, the geotextile, untreated building paper, hay or straw is to be immediately installed and the
trench backfilled with native soil. If the trenches cannot be immediately backfilled, they should be temporarily covered with an
impervious material such as treated building paper to prevent sidewall collapse and siltation into the aggregate.

(vii) The earth backfill is to be mounded slightly above the original ground level to allow for settling and after settlement the entire area
should be graded without the use of heavy equipment and seeded with grass.

(i) Trenches are excavated at least two feet into the useable layer and backfilled with aggregate or coarse sandy material
containing a low percentage of fines more permeable than the underlying material to a level 30 inches below the original ground surface.

(ii) An absorption trench system as described in Section 75-A.8(b) is constructed in the upper 30 inches of the excavation.

Shallow Trench Septic Systems

(1) Site Requirements for shallow septic system absorption trenches

These systems are used where there is at least two feet but less than four feet of useable soil and/or separation to boundary conditions.

(2) Design criteria for shallow septic absorption trenches

(i) A minimum two foot separation must be maintained between the bottom of each trench and all boundary conditions.

(ii) The bottom of each trench must not be above the original ground surface.

(iii) Material of the same permeability as the underlying original soil shall be used as fill material. The depth of the fill shall not be
greater than 30 inches above the original ground elevation.

(iv) An absorption trench system as described in Section 75-A.8(b) is designed using the percolation of the underlying original soil.

(3) Construction of Shallow Septic System Absorption Trenches

(i) Heavy equipment shall be kept out of the absorption area.

(ii) Fill material is carefully placed within the absorption area.

(iii) The edge of the fill material shall be tapered at a slope of no greater than one vertical to three horizontal. On sloped sites a
diversion ditch shall be placed on the uphill side to prevent runoff from entering the fill.

(iv) The absorption trench system is constructed in the fill material, extending into the existing natural soil.

Question: Can I Backfill the Septic drainfield Trenches with Wet Soil during Field Construction?

I recently installed leaching chambers and before I could backfill the trenches it rained for a couple of hours, is it ok to use the wet backfill to fill the trenches? - B.D.

Reply:

OPINION-DF: A competent onsite septic field construction inspection by an expert may find additional concerns that need to be addressed to assure a long drainfield life. That said, here are some things to consider:

Provided you are installing the required gravel under and around the drainfield piping, backfilling with wet soil may not be a problem

We say "may not be" because of not the so much the soil itself, as soil is wet after backfill when it rains, but rather because depending on trench depth and how the operator runs the equipment, driving over some wet soils (depending on soil composition itself), or piling deep amounts of wet soil in a trench may compact the soil more than it would have been compacted if filled dry.

Our opinion is that because of its added weight, filling to depths more than 30" might compact soils unnecessarily.

But a much more serious concern would be driving the backhoe or other construction equipment over the trenches, makes for a high risk of excessive soil compaction, especially driving the equipment over the trenches.

So soil that is not clay, and drainfield trenches that are less than 30" deep from top of gravel (over the pipes) to surface, mean you may be ok.

But driving the earth moving equipment around over the drainfield trenches themselves (or in the future driving anything over the drainfield) risks damage to the fields by soil compaction or even crushing and breaking the drainfield piping. Don't do it - backfill with care, driving equipment in the space between the drainfield trenches rather than over them.

(1) A cut and fill septic system is an absorption trench system installed on
sites where impermeable soil overlays a permeable soil.

(2) Site Requirements for cut and fill septic systems

Cut and fill septic systems may be used where all the following conditions
are found:

(i) A soil with a percolation rate slower than 60 minutes per inch, such as clay or clay loam, overlays a useable soil with a percolation rate faster than 60 minutes per inch;

(ii) At least three feet of useable soil is available beneath the tight soil;

(iii) All minimum vertical and horizontal separation distances can be maintained as described in Table 2.

(3) Design criteria for cut and fill septic systems

(i) It shall provide for the removal of the overlaying unusable soil and replacement by soil having a percolation rate comparable with the
underlying soil;

(ii) An absorption trench system is designed as described in Section 75-A.8(b).

(iii) The required length of absorption trench is based upon the percolation of the underlying soil or the fill material, whichever has
the slower percolation (lower permeability).

(4) Construction of cut and fill septic systems

(i) The area excavated and filled must provide at least a five foot buffer in each direction beyond the trenches.

(ii) The material placed above the trenches shall have a percolation rate faster than 60 minutes per inch.

(iii) Original surface material shall not be used as backfill above the trenches.

(iv) The surface area of the fill system must be mounded and graded to enhance the runoff of rainwater from the system and seeded to grass.

Absorption Bed Systems - (g) Absorption Bed Septic Systems

(1) General

An absorption bed system operates on a principal similar to the absorption trench except that several laterals, rather than just
one, are installed in a single excavation. This reduces the effective sidewall infiltration area per linear foot of lateral or leach line.

(2) Site Requirements for absorption bed septic system

(i) A bed system may be built in soils with a percolation rate between one and 30 minutes per inch. A bed shall not
be built where the soil evaluation indicates silty loam, clay loam, or clay.

(ii) Slope of the site shall not exceed eight percent.

(iii) Bed systems are more practical on sites that are long and narrow with a minimal slope.

(3) Design Criteria for absorption bed septic systems

(i) Pressure distribution is required for the installation of an absorption bed system. The local health department having jurisdiction
may allow the use of siphon dosing on specific sites.

(ii) The maximum width of the bed shall be 20 feet. The maximum length of each lateral from a pressure manifold shall be 100 feet. Utilizing a
center manifold system, a bed may then have a maximum length of 200 feet. Laterals for siphon dosing systems in beds are limited to 75
feet.

(iii) The depth of the bed shall be between 18 and 30 inches below original ground level.

(iv) Laterals shall be spaced five (5) feet apart. Two and one-half feet (2 1/2') must be provided between the laterals and the sidewalls.
In the maximum width of 20 feet, only four laterals may be installed.

(v) Using pressure distribution with a center manifold, a bed system shall have maximum dimensions of 205 feet by 20 feet.

(vi) The required bed bottom area shall be calculated from the application rates shown in Table 5 - below

If you scrolled down in this document to look for information on Seepage Pit construction, that subchapter discussing the design and use of seepage pits for
onsite wastewater disposal is published as a separate web page: SEEPAGE PITS.

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Technical Reviewers & References

[1] US EPA Onsite Wastewater Treatment Systems Manual [online copy, free] Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm Onsite wastewater treatment and disposal systems,
Richard J Otis, published by the US EPA. Although it's more than 20 years old, this book remains a useful reference for septic system designers.
U.S. Environmental Protection Agency, Office of Water Program Operations; Office of Research and Development, Municipal Environmental Research Laboratory; (1980)

[5] "Installers Manual for Conventional Onsite Domestic Wastewater Treatment and Disposal Systems", Department of Environmental Conservation, Division of Environmental Health Drinking Water and Domestic Wastewater Program, Alaska Department of Environmental Conservation, 1 Aug 2000, Anchorage Offices, 555 Coredova, Anchorage AK 99501, Tel: 907-269-7500. retrieved 17 July 2012, original source: http://dec.alaska.gov/water/wwdp/onsite/pdf/Certified_Installer%27s_Manual.pdf [Copy on file as Alaska_Certified_Installer's_Manual.pdf].
Notice: [Quoting]This document contains information regarding the installation of onsite se3wer systems for single-family and duplex residences. It must be used by Certified Installers and homeowners who are subject to 18 AAC 72. Additional requirements are included in 18 AAC 72. If there is a conflict between the provisions of this manual and 18 AAC 72, 18 AAC 80, or other state regulations, the regulations language controls. AEDC offices.
The regulations cited above for Alaskans can be found at http://www.alaska.gov/dec./deh/water/ci.htm

[9] Wells and Septic Systems, Alth, Max and Charlet, Rev. by S. Blackwell Duncan, $ 18.95; Tab Books 1992. We have found this text very useful for conventional well and septic systems design and maintenance --DF.
Quoting an Amazon description:Here's all the information you need to build a well or septic system yourself - and save a lot of time, money, and frustration. S. Blackwell Duncan has thoroughly revised and updated this second edition of Wells and Septic Systems to conform to current codes and requirements. He also has expanded this national bestseller to include new material on well and septic installation, water storage and distribution, water treatment, ecological considerations, and septic systems for problem building sites.

[16] Soil Test Pit Preparation, fact sheet, Oregon DEQ Department of Environmental Quality, original source www.deq.state.or.us/wq/pubs/factsheets/onsite/testpitprep.pdf The Oregon DEQ onsite water quality program can be contacted at 811 South Ave, Portland OR 97204, 800-452-4011 or see http://www.oregon.gov/DEQ/

Document Sources used for this web page include but are not limited to: Agricultural Fact Sheet #SW-161 "Septic Tank Pumping," by Paul D. Robillard and
Kelli S. Martin. Penn State College of Agriculture - Cooperative Extension, edited and annotated by
Dan Friedman (Thanks: to Bob Mackey for proofreading the original source material.)

Builder's Guide to Wells and Septic Systems, Woodson, R. Dodge: $ 24.95; MCGRAW HILL B; TP;
Quoting from Amazon's description: For the homebuilder, one mistake in estimating or installing wells and septic systems can cost thousands of dollars. This comprehensive guide filled with case studies can prevent that. Master plumber R. Dodge Woodson packs this reader-friendly guide with guidance and information, including details on new techniques and materials that can economize and expedite jobs and advice on how to avoid mistakes in both estimating and construction. Chapters cover virtually every aspect of wells and septic systems, including on-site evaluations; site limitations; bidding; soil studies, septic designs, and code-related issues; drilled and dug wells, gravel and pipe, chamber-type, and gravity septic systems; pump stations; common problems with well installation; and remedies for poor septic situations. Woodson also discusses ways to increase profits by avoiding cost overruns.

Country Plumbing: Living with a Septic System, Hartigan, Gerry: $ 9.95; ALAN C HOOD & TP;
Quoting an Amazon reviewer's comment, with which we agree--DF:This book is informative as far as it goes and might be most useful for someone with an older system. But it was written in the early 1980s. A lot has changed since then. In particular, the book doesn't cover any of the newer systems that are used more and more nowadays in some parts of the country -- sand mounds, aeration systems, lagoons, etc.

Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.

The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors.Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.

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The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.

Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.